Although the basic phenomena involved are unknown at this time, investigations in this laboratory have demonstrated a causal relationship between carcinoma of the urinary bladder and infection with the helminth parasite, Schistosoma haematobium. Since the S. haematobium-capuchin monkey (Cebus) combination, to date, has been most successful, this system is being employed in an attempt to learn more about bladder carcinogenesis. Lesions, some of which have been histopathologically confirmed as transitional cell carcinoma, have been transferred from the bladder to other sites in the capuchin body. Although there is no evidence that tissues transferred (subperitoneal, intramuscular, subcutaneous) have the potentiality for establishment or growth, this is one of the parameters which must be evaluated to characterize schistosome induced neoplasia of the bladder. Subjects now under study will be monitored for parasitological and clinical manifestations of disease during the next year to determine whether extended duration of infection and/or continued association of the schistosome with the bladder will account for further alterations of bladder involvement. New capuchins, already patent for infection, will be included in the study series for the next period. Urine cytology will be employed in an attempt to judge status of bladder involvement attendant to infection. Selected hosts will be examined by open cystotomy. Lesions will be sampled for histopathological evaluation and some will be transferred to other sites in the same host or to other noninfected, control capuchins if lesions permit.